add paging

src/main/java/microservice/common/paging/Href.java

+package microservice.common.paging;
+
+/**
+ * Created by amir on 23/03/17.
+ */
+public class Href {
+    public static final int CAPACITY = 64;
+    String href;
+
+    public Href(String url, int number, int size) {
+        this.href = new StringBuilder(CAPACITY)
+                .append(url)
+                .append('?')
+                .append("page=")
+                .append(number)
+                .append("&size=")
+                .append(size)
+                .toString();
+    }
+
+    public String getHref() {
+        return href;
+    }
+
+}

src/main/java/microservice/common/paging/Links.java

+package microservice.common.paging;
+
+/**
+ * Created by amir on 23/03/17.
+ */
+public class Links {
+    Href self = null;
+    Href next = null;
+    Href first = null;
+    Href last = null;
+
+    public Links(String url,Page page){
+        /**
+         * calculate links
+         */
+        self = new Href(url,page.number,page.size);
+        first = new Href(url,0,page.size);
+        last = new Href(url,page.totalPages - 1, page.size);
+        if (page.number < (page.totalPages - 1))
+            next = new Href(url,page.number + 1, page.size);
+    }
+
+
+    public Href getSelf() {
+        return self;
+    }
+
+    public Href getNext() {
+        return next;
+    }
+
+    public Href getFirst() {
+        return first;
+    }
+
+    public Href getLast() {
+        return last;
+    }
+
+}

src/main/java/microservice/common/paging/Page.java

+package microservice.common.paging;
+
+/**
+ * Created by amir on 23/03/17.
+ */
+public class Page {
+    boolean last;
+    long totalElements;
+    int totalPages;
+    int numberOfElements;
+    Sort sort;
+    boolean first;
+    int size;
+    int number;
+
+    public Page(long totalElements, int numberOfElements, Sort sort, int number,int pageMaxSize) {
+        this.totalElements = totalElements;
+        this.numberOfElements = numberOfElements;
+        this.sort = sort;
+        this.number = number;
+        this.size = pageMaxSize;
+        if (totalElements <= pageMaxSize)
+            this.totalPages = 1;
+        else {
+            this.totalPages = (int) (totalElements / pageMaxSize);
+            if ((totalElements % pageMaxSize) != 0)
+                this.totalPages++;
+        }
+        if (number == 0)
+            first = true;
+        if (totalPages == 0 || number == (totalPages - 1))
+            last = true;
+    }
+
+    public boolean isLast() {
+        return last;
+    }
+
+    public long getTotalElements() {
+        return totalElements;
+    }
+
+    public int getTotalPages() {
+        return totalPages;
+    }
+
+    public int getNumberOfElements() {
+        return numberOfElements;
+    }
+
+    public Sort getSort() {
+        return sort;
+    }
+
+    public boolean isFirst() {
+        return first;
+    }
+
+    public int getSize() {
+        return size;
+    }
+
+    public int getNumber() {
+        return number;
+    }
+
+}

src/main/java/microservice/common/paging/PageBuilder.java

+package microservice.common.paging;
+
+import com.fasterxml.jackson.databind.node.ArrayNode;
+
+/**
+ * Created by amir on 23/03/17.
+ */
+public interface PageBuilder<T> {
+
+    T buidPage(String url,
+               ArrayNode content,
+               int pageNumber,
+               long totalElements,
+               int pageMaxSize);
+    T buidPage(String url,
+               ArrayNode content,
+               int pageNumber,
+               long totalElements,
+               int pageMaxSize,
+               String sortProperty,
+               boolean sortAscending);
+}

src/main/java/microservice/common/paging/PageBuilderJsonNodeImpl.java

+package microservice.common.paging;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.node.ArrayNode;
+import com.fasterxml.jackson.databind.node.JsonNodeFactory;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+import common.JsonHandler;
+
+/**
+ * Created by amir on 22/03/17.
+ *   {
+ *      "content":[
+         { ...},
+         { ...},
+         ....
+         ],
+         "_links": {
+             "self": {
+             "href": "http://localhost:8012/ds/entities/MCX/entities?page=0&size=50"
+             },
+             "next": {
+             "href": "http://localhost:8012/ds/entities/MCX/entities?page=1&size=50""
+             },
+             "first": {
+             "href": "http://localhost:8012/ds/entities/MCX/entities?page=0&size=50""
+             },
+             "last": {
+             "href": "http://localhost:8012/ds/entities/MCX/entities?page=3&size=50"
+             }
+         },
+         "page":{
+             "last": false,
+             "totalElements": 174,
+             "totalPages": 4,
+             "numberOfElements": 50,
+             "sort": null,
+             "first": true,
+             "size": 50,
+             "number": 0
+         }
+     }
+ */
+public class PageBuilderJsonNodeImpl implements PageBuilder<JsonNode> {
+
+    static final private JsonNodeFactory nodeFactory = JsonNodeFactory.instance;
+
+    public JsonNode buidPage(String url,
+                             ArrayNode content,
+                             int pageNumber,
+                             long totalElements,
+                             int pageMaxSize,
+                             String sortProperty,
+                             boolean sortAscending){
+        ObjectNode pageNode = nodeFactory.objectNode();
+        /**
+         * preparing
+         */
+        Sort sort = null;
+        if (sortProperty != null)
+            sort = new Sort(sortProperty,sortAscending);
+        Page pageInfo = new Page(totalElements,content.size(),sort,pageNumber,pageMaxSize);
+        Links links = null;
+        if (totalElements > 0 && content.size() > 0)
+            links = new Links(url,pageInfo);
+
+        /**
+         * bulding
+         */
+        pageNode.set("content",content);
+        pageNode.set("_links", JsonHandler.getJsonNodeFromObject(links));
+        pageNode.set("page", JsonHandler.getJsonNodeFromObject(pageInfo));
+        return pageNode;
+    }
+
+    public JsonNode buidPage(String url,
+                             ArrayNode content,
+                             int pageNumber,
+                             long totalElements,
+                             int pageMaxSize){
+        return buidPage(url,content,pageNumber,totalElements,pageMaxSize,null,false);
+    }
+
+
+}
\ No newline at end of file

src/main/java/microservice/common/paging/Sort.java

+package microservice.common.paging;
+
+/**
+ * Created by amir on 23/03/17.
+ */
+public class Sort {
+    String property;
+    boolean ascending;
+
+    public Sort(String property, boolean ascending) {
+        this.property = property;
+        this.ascending = ascending;
+    }
+
+    public String getProperty() {
+        return property;
+    }
+
+    public boolean isAscending() {
+        return ascending;
+    }
+
+}